How to Set Path Environment Variable using CMake and Visual Studio to Run Test

For setting custom project setting in Visual Studio from CMake you can use a XML file as a template which can be configured from CMake to work as the .user file.
At my work we use this to set custom debug parameters.

Check the directory containing the generated .vcxproj files for the user settings in the .user files. Here is a snippet of an example UserTemplate.vcxproj.user file we use.

    <?xml version="1.0" encoding="Windows-1252"?>
      <VisualStudioUserFile
        ProjectType="Visual C++"
        Version="9.00"
        ShowAllFiles="false"
        >
        <Configurations>
            <Configuration
                Name="Debug|@USERFILE_PLATFORM@"
                >
                <DebugSettings
                    Command="@USERFILE_COMMAND_DEBUG@"
                    WorkingDirectory="@USERFILE_WORKING_DIRECTORY_DEBUG@"
                    CommandArguments="@USERFILE_COMMAND_ARGUMENTS_DEBUG@"
                    Attach="false"
                    DebuggerType="3"
                    Remote="1"
                    RemoteMachine="@USERFILE_REMOTE_MACHINE_DEBUG@"
                                <!-- More settings removed for snippet -->
                />
            </Configuration>
                <!-- Rest of Configurations -->

Another example of a UserTemplate.vcxproj.user to set the PATH variable, would be:

    <?xml version="1.0" encoding="utf-8"?>
    <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
      <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
        <LocalDebuggerEnvironment>PATH=..\Your_path;%PATH%".</LocalDebuggerEnvironment>
        <DebuggerFlavor>WindowsLocalDebugger</DebuggerFlavor>
      </PropertyGroup>
    </Project>

Setting the UserTemplate.vcxproj.user file next to your CMakeLists.txt file, you can inject any needed variables from CMake into the .vcxproj.user file of your builded project.
In CMake you can set the appropiate CMake variables (and add more in the template file if you need them). Next you can do something like this to configure the file.

    # Find user and system name
    SET(SYSTEM_NAME $ENV{USERDOMAIN} CACHE STRING SystemName)
    SET(USER_NAME $ENV{USERNAME} CACHE STRING UserName)

    # Configure the template file
    SET(USER_FILE ${_projectName}.vcxproj.${SYSTEM_NAME}.${USER_NAME}.user)
    SET(OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/${USER_FILE})
    CONFIGURE_FILE(UserTemplate.vcxproj.user${USER_FILE} @ONLY)

If you don’t care about the system and the user name, the following configuration would be enough.

    # Configure the template file
    SET(USER_FILE ${_projectName}.vcxproj.user)
    SET(OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/${USER_FILE})
    CONFIGURE_FILE(UserTemplate.vcxproj.user ${USER_FILE} @ONLY)